Determination of second-order elastic constants of cyclotetramethylene tetranitramine (β-HMX) using impulsive stimulated thermal scattering

Abstract

Second-order elastic constants of pentaerythritol tetranitrate and cyclotrimethylene trinitramine using impulsive stimulated thermal scattering J. Appl. Phys.The second-order elastic constants for cyclotetramethylene tetranitramine ͑␤-HMX͒ single crystals were determined using the impulsive stimulated thermal scattering ͑ISTS͒ method. Despite the low symmetry of these crystals, the complete set of 13 elastic constants were determined accurately from acoustic velocity measurements using samples cut parallel to three different crystal planes. Our acoustic velocities are consistent with the limited sound speed data available from ultrasonic measurements. However, significant differences are observed between the elastic constants determined from our experiments and those obtained previously using Brillouin scattering. Our results demonstrate the usefulness and efficiency of the ISTS method for determining the full set of elastic constants of low-symmetry molecular crystals, including energetic crystals.

An Anisotropic Elastoviscoplasticity Model of Thermomechanical Responses of Shocked β‐HMX and α‐RDX Single Crystals

“…It belongs to a monoclinic system (a = 6.54 Å, b = 11.05 Å, c = 7.37 Å, β = 102.8°) with P2 1 /n space group and has two molecules per unit cell [41]. Elastic constants could be determined by impulsive stimulated thermal scattering [42], Brillouin scattering [43] and molecular dynamics simulations [44]. Zamiri and De [45] suggested the elastic constants from molecular dynamics simulations could best fit the experimental results.…”

“…Lattice parameters of α-RDX are a = 13.182 Å, b = 11.574 Å, c = 10.709 Å, and α = β = γ = 90°. Elastic constants have been obtained through Brillouin scattering [52], resonant ultrasound [53], and impulsive stimulated thermal scattering [42]. In this work, we choose the nine elastic coefficients obtained from resonant ultrasound [53] and temperature and pressure derivatives obtained from molecular dynamics simulations [54] (Table 7).…”

Mesoscale modeling of dislocations in molecular crystals

“…Molecular dynamics simulations of shock loading of energetic crystals give further insight into the mechanisms of plastic deformation in molecular crystals in general [28][29][30][31][32][33]. Jaramillo et al [28] report, via atomistic simulations, slip planes and onset of amorphization of cyclotetramethylenetetranitramine (HMX) while the work of Cawkwell et al [29] shows the formation of regions of localized shear deformation in RDX.…”

Investigating deformation and mesoscale void creation in HMX based composites using tomography based grain scale FEM

“…HMX exhibits monoclinic symmetry and is thus represented by 13 independent elastic stiffness coefficients. HMX grains were modeled using anisotropic linear elasticity with coefficients reported by Sun et al [19], [cf. also 20].…”